FACTBOX - Key facts about new Belgian prime minister

* Van Rompuy, 61, has been president of the lower house of parliament since July 2007 and has at times been critical of the Leterme government.

* Budget minister 1993-1999 in the Christian Democrat-led government, he reduced Belgium's public debt sharply from 130 percent of gross domestic product in the year he took office. A budgetary hardliner, he has criticised the previous government's plan to spend its way out of recession and increase the deficit.

* He has written six books, mainly on social and political issues, and is an avid blogger.

* He is respected among French speakers and was among the most palatable to them of the likely successors to Leterme. Many believe he takes an even-handed approach to disputes between French and Dutch speakers.

* After saying he did not want to replace Leterme as prime minister, he appears to have given in to pressure from fellow Flemish Christian Democrats who feared the liberals might otherwise insist on the return of former PM Guy Verhofstadt.